Tap process for hard workpieces

ABSTRACT

A process and apparatus for producing screw threads in hard material workpieces with a series of taps. The present invention employs a threaded bore formed in a bracket assembly to align and position multiple taps on a rotary machine. The taps are used in sequence to cut threads progressively deeper into a substrate. The present invention provides a method of aligning and orienting each progressive tap to begin its cut at the same initial starting point.

FIELD OF THE INVENTION

The present invention relates to an improved method and apparatus forforming internal screw threads with taps.

BACKGROUND

Current methods of tapping, or forming threads in a hole, generally usea hard steel tap with a tapered threaded first end that cuts the threadsas it is rotated at a second end. Longitudinal grooves, or flutes, whichmay be straight or helical, interrupt the spiral thread form to generatecutting elements, and to provide clearance space for the chips generatedby the cutting elements. Binding of the tap requires increasing torqueat the driving end to advance it. The increased twisting of the tap maybreak it, often leaving the cutting end broken and stuck in the hole.This not only results in loss of the tap, but often means scrapping thepart due to the high cost of removal of the broken tap. After a hole istapped, the tap is removed by reverse rotation.

Because of the danger of tap breakage, it is common practice toperiodically reverse rotate to break off the chips.

The method of forming internal threads in workpieces that must behardened, such as in steel alloy, begins when a tap drill bore isdrilled into the soft workpiece and then a tap would be used to cut outthe internal threads. Then, after the thread is completed, the workpiecewould be subjected to heat treatment to harden the workpiece material.When attempts have been made to form internal threads in a hardenedworkpiece, the machining operation was very difficult, and the tapswould break and fail. Breakage is almost certain when tapping smalldiameter holes, because the web of the tap with it's small cross sectionis much weaker and less resistant to the required cutting torque.

When workpiece materials such as steel alloys are heat treated afterinternal threads are made, they have a tendency to cause the threads andor the workpiece surfaces to deform, making true thread form andaccurate location difficult to control.

There is a need in the industry for a tapping system that can quicklymanufacture internal threads within an acceptable tolerance in hardworkpieces.

The present invention provides a method of tapping a hole in a hardworkpiece wherein the internal threads are formed quickly and withprecision. These and other objects and advantages of the invention, aswell as the details of illustrative embodiments, will be more fullyunderstood from the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section view of the assembly of the present invention.

FIG. 2 is a side view representation of a tap that can be accuratelypositioned with the alignment assembly of the present invention.

FIG. 3 is a detailed side view of a standard tap plus a portion of thealignment assembly in its assembled position prior to connection to themain tool fixture.

FIG. 4 illustrates a tap fixed to a chuck.

FIG. 5A is a cross section view of the fixed support block portion ofthe alignment assembly shown in FIG. 1.

FIG. 5B is a top view of FIG. 5A.

FIG. 6A is a partial view of a representation of the first step in atapping process of a first embodiment of the present invention cuttingan initial rough thread in a tap drill bore. In this embodiment thepitch diameter is reduced from the full thread form.

FIG. 6B is a partial view of a representation of a second step in thetapping process of the first embodiment of present invention. In thisembodiment the pitch diameter is reduced to a lesser amount than thefirst step tap from the full thread form.

FIG. 6C is a partial view of a representation of a third step in thetapping process of a first embodiment of the present invention. In thisillustration the tap represents the full thread form.

FIG. 6D is a partial view of the final internal threads formed in aworkpiece by the first embodiment.

FIG. 6E is a partial view of a representation of the first step in atapping process of a second embodiment of the present invention cuttingan initial rough thread in a tap drill bore. This example illustrates areduced major diameter in place of a reduced pitch diameter.

FIG. 6F is a partial view of a representation of a second step in thetapping process of a second embodiment of the present invention. Thisexample illustrates a reduced major diameter in place of a reduced pitchdiameter.

FIG. 6G is a partial view of a representation of a third step in thetapping process of a second embodiment of the present invention. In thisillustration the tap represents the full thread form.

FIG. 6H is a partial view of the final internal threads formed in aworkpiece by the second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

An improved method of making internal threads with a series of taps usedin sequence is disclosed in the instant invention. The threads formed inthe embodiment of the present invention disclosed herein are produced bycutting. However, it is contemplated that the disclosed presentinvention could alternatively have a similar application in “forming”threads in metal substrates as apposed to cutting out the threads. Insuch an alternative embodiment of the present invention the taps wouldextrude the thread form rather than cut threads in the metal substrate.One embodiment of a tap used in the present invention is illustrated inFIG. 2. The shape of the tap is only representative of one style of tapthat might be used in accordance with the invention as will beappreciated and apparent to an ordinary artisan.

A plurality of universal milling tapping and boring machines and specialnumerical controlled machines with the ability to accurately changetools in their spindle are well known in the industry. Universal millingand boring machines each have the capability of holding a plurality oftools, each of which perform one or more machining operations on a workpiece in accordance with a programmed computer. Some machines arecapable of holding a few to hundreds of tools on an automatic toolchanger having a spindle or a magazine on which tool chucks/holders arepositioned, each chuck/holder with a tool having a particular machiningfunction. The process being described by this present invention workswhether the tools are changed manually or automatically. Automatic toolchanging is a standard feature on most machine spindles in the industry.

During operation of the universal boring and milling machines, once acutting tool is connected to the spindle, it performs its programmedcutting function until another tool is needed to begin the next cuttingoperation step. Machine tools in the industry have rotary drivenspindles that, after each machining operation, the spindles arepositioned to the same set starting point. That is, after a new tool isconnected to the spindle, the spindle returns back to its original zeroset point. The spindle is three dimensionally returned to its originalthree dimensioned position, to the same zero set point, including thesame angular orientation and axial position prior to beginning the nextprogrammed operational step. This zero set point spindle positioncontrol feature is well known in the industry and included in all rigidand synchronous tapping CNC routines.

Universal tool holders/chucks are used to connect tools to such spindlesand magazines. These tool holders/chucks typically have a taperedfrustoconical section, as for instance shown at 41 in FIG. 4. Somewell-known industry standards, such as HSK, KM, and CAPTO toolingsystems, have cone surfaces but no rearward pin 43. The tapered section41 is received in a frustoconical cavity within a spindle on a rotarymachine. The precise fit between spindle and tool holder tapers providesthe accuracy, orientation and the rigidity needed to perform themachining operation. Some method of retention is also provided withinthe spindle in the form of grippers and pull back systems. There is notjust one standard chuck/holder in the rotary machine cutting industry,but several tool holder/chuck shapes and sizes, including but notlimited to CV, BT, HSK, CAPTO, KM holder/chucks and a few othercommercially available standards. A keyway alignment slot 11 as shown inFIG. 4 is integral to a typical tool holder. Similar keyway drive slots,or orientation characteristics exist on other standard taper tools.Another similar keyway slot 11 (not shown) is on the opposite side ofthe chuck/holder one hundred eighty (180) degrees around thecircumference of the chuck/holder in direct alignment with the firstkeyway slot. The keyway slots 11 are adapted to receive drive pins orkeys (“drive dogs”) as shown in FIG. 6 of U.S. Pat. No. 6,231,282, andas shown at 8 in U.S. Pat. No. 5,009,555. The pins snugly fit within thekeyway slots 11 and resist any possible rotation of the chuck/holderabout its longitudinal axis that otherwise might occur on account of thehigh torques and forces applied to the cutting tool during operation.The cooperating keyway on the chuck with the key on the spindle alsoassist in properly aligning the chuck on the machining spindle.

FIG. 2 illustrates an internal threading tap 20 according to oneembodiment of the invention. The tap is received in a chuck 10, see FIG.4, as well known in the industry. The chuck includes a collet 40 forclamping securely onto the tap 20. U.S. Pat. No. 5,118,231 and 5,009,555disclose collet/chucks and are hereby incorporated into thisspecification in their entirety. FIG. 7 in U.S. Pat. No. 5,118,231discloses a chuck with an integral collet for receiving a drill and/orother cutting tools. The method of clamping the tap within the collet isnot an essential feature of the present invention. It is contemplatedthat in the present invention other well-known tool clamping methods forsecuring the position of the tap, including hydraulic, shrink whistlenotch, and other well-known clamping methods may alternatively beemployed to fix the tap into position after it has been properly alignedin accordance with the present invention.

As discussed above, the present invention is adapted to be incorporatedwith a well-known universal milling, tapping, and boring machines. Theinvention employs a universal milling, tapping, and boring machine tosequentially run a series of taps to cut out an internally threaded boreinto a workpiece. Initially, a tap drill bore is formed in theworkpiece. Next, a first tap having a shape similar to FIG. 2, withmajor diameter “C”, slightly larger than the diameter of the tap drillbore, is first used to initially rough out the thread within the boreduring a cutting operation step. The rough threads formed by the firsttap are then followed by a second tap, performing a second cuttingoperation step, the second tap having a larger major diameter “C” thanthe first tap. Then finally, another third tap with even a larger majordiameter “C” than the second tap is used to cut the thread deeper tofinish the thread into its full size, in a third cutting operation step.Although the invention described immediately above discloses threeindividual taps used in sequence, the number of taps employed by thepresent invention is not limited to three. It could be two taps or morethan three taps. The present invention introduces a new method ofaccurately aligning a plurality of taps to sequentially cut/formthreads. The present invention is particularly suitable forcutting/forming threads when a one operation step tapping cycle- toproduce the entire thread form is not viable. For instance a oneoperation step tapping cycle does not work well in hard workpieces.

Most universal rotary machines for boring, tapping, and milling in theindustry have the spindle zero set point feature described above. Thezero set point feature returns the spindle back to its originalorientation upon completion of a machining cycle with a selected tool.Each selected tool in a rotary machine has the same initial startingpoint, zero set point. The present invention is used in combination withsuch rotary machines having this zero set point feature. With thepresent invention, each subsequent tap in the series can be easilyoriented axially and radially to begin cutting at the same position sothat a subsequent tap is not misaligned with a roughed out cut made witha proceeding tap. If a subsequent tap is not accurately aligned, asecond misaligned cut results. The second cut does not increase therough cut fuller as intended, but forms a second thread cut askew of thefirst rough cut or possibly the second tap breaks. It is necessary tohave an accurate system wherein all the taps used in a series, uponconnection to the rotary machine, are each positioned so as to have thesame axial position and angular orientation when the spindle is at zeroset point.

FIG. 1 illustrates an alignment assembly 22 for accurately positioning atap 20 radially and axially within a chuck 10. The alignment assembly 22comprises a bracket 30 and fixed support block 8. The bracket 30includes a bottom clamp assembly 14, which is fastened onto a supportblock 8. The support block 8 has a central axis Y—Y and a key 6 or keyson the top surface of the block 8.

In the invention, the keyway slots 11 and the frustoconical taperedportion 41 on the chuck are used to consistently fix and orient a chuck10 into position in the same manner that these elements do whenever thechuck is connected to the spindle. FIG. 5A illustrates a support block 8for assisting in accurately positioning each universal chuck employed tohold a tool. As shown in phantom lines in FIG. 5A a centrally locatedcavity 3 having a frustoconical upper portion and lower cylindricalportion is formed within the support block 8. The cavity 3 is shaped andsized so that the contacting cooperation of the chuck's frustoconicaltapered portion 41, FIG. 4 with the frustoconical portion of the cavity3, FIG. 5A centers the chuck within the cavity 3. The support block 8includes one or two keys 6 on its top surface. The one or two keys 6 areshaped and sized to be snugly received within the chuck keyway slots 11,FIG. 4. The keys and key slots, are not intended to be limited to theshape disclosed in the illustrated embodiment. Alternatively the key 6and key slot 11 may be corresponding rectangular, triangular, hexagon,polygon, oval or an irregular shape for instance as would be appropriateto accommodate the key slots 11 of a chuck/holder being loaded with atap.

As well known in the art, most chucks have two notches oriented onopposite sides of the chuck one hundred eighty (180) degrees apart fromeach other. To ensure that the chuck is not positioned (180) degrees outof alignment some spindles in the prior art have key size or depthdifferences so that the chuck is located in the same orientation eachtime. Other tools and spindles with symmetrical-identical keys can beused in this process when the tool holders are placed on the block forreceiving a tap, and one of the notches on the chuck and one key on theblock are physically marked or identified for alignment purposes. Thisdemarcation would insure that only one tool orientation is maintained inthe present invention.

A clamp assembly 14, see FIG. 1, snugly clamps against the support block8, which in this embodiment has a generally round cross-section,although it may alternatively have a square, rectangular or otherirregular shaped cross-section. The clamp assembly includes two apposingmembers 5 and 7 that clamp together against the support block. A pair ofbolts 16 are positioned on opposite sides of the support block 8 totighten members 5 and 7 together. The members 5/7 generally have asemi-circular inner surface. The semi-circular inner surface correspondsin shape to the exterior surface of the support block, both members 5/7clamp together against the external surface of the support block. Theradial-angular positioning of the bracket assembly 30 relative to theblock 8 is not critical to the function of the process; however, therelative axial position of the bracket assembly 30 with respect to theblock 8 is critical to the proper alignment of each tap being used tosequentially cut threads into a substrate. It should be appreciated thatthe bolts 16 allow for axial adjustment of the bracket assembly 30 sothat the cutting depth, the length “H” in FIG. 1, that the tap extendsbeyond the collet, can be varied and/or to accommodate longer or shorterchucks. The invention is not intended to be limited to the fasteningmembers 5/7 in the illustrated embodiment, but that other well-knownfastening means could alternatively be employed to fix the bracketassembly 30 into its axial position about the block 8.

The cantilever arm 18 of the invention has a first internally threadedblind alignment bore 17 adjacent to one end of the arm 18 and a secondsmooth throughbore 15, FIG. 3 (phantom lines) at an opposite end forreceiving the threaded portion of thumb screw 19. The first threadedbore 17 is precisely made so that a tap 20 can be accurately aligned andpositioned therein. The first threaded bore 17 and second throughbore 15have central longitudinal axes that are both perpendicular to thelongitudinal axis of the cantilever arm 18. The bottom surface 27 of thebore 17 can be configured to have a geometry that conforms to the bottomsurface 26, see FIG. 3 of the tap as shown in FIG. 2. The depth “A” thatthe blind bore extends into the cantilever arm 18 as shown in FIG. 3 canbe precisely machined. The pitch and geometry of the internal threads inthe blind alignment bore 17 are nearly identical to the internal threaddesired to be formed in a hard material workpiece. The smooththroughbore 15 is large enough to permit rotation of the cantilever arm.

As shown in FIG. 3, a tap 20 is preset by screwing the tap until itbottom's out into a temporary position in a threaded alignment bore 17formed in the cantilevered arm 18. The cantilevered arm 18 is thenfastened to a top surface of the bracket 30 support arm, see FIG. 1, bya knurled screw 19; thumbscrew, fastener, clamp or other equivalentmeans for attaching the cantilever arm 18 to the bracket.

The tap configuration illustrated in FIG. 2 and cooperating threads inthe alignment bore 17 of the cantilever arm 18 are illustrative of oneembodiment of a cantilever arm of the present invention having athreaded bore 17 suitable for receiving a tap as shown in FIG. 2 orsimilarly designed. It should be appreciated that other cantilever arms18 having bores 17 with other different thread configurations may beemployed to accommodate taps having different thread shapes and sizes.

As well known in the art, every tap has a leading cutting edge asillustrated in FIG. 2 at 28. The leading cutting edge 28 is the smallestcutting diameter on a tap, see 26 in FIG. 2. During a tapping operation,where the leading cutting edge first contacts the tap drill bore of theworkpiece, is where the helical groove of the internal thread begins. Itis essential that any subsequent tap that is employed to furtherincrease the thread depth, in a series of taps as described above, mustbegin cutting at the same location where the first tap began cutting thehelical thread. It should be appreciated that an apparatus is requiredthat will perform the function of correctly positioning and orientingthe leading cutting edge of each subsequent tap used in series so thateach tap will begin cutting at the same location on the workpiece.

The method of aligning a first pilot tap in a series of taps of thepresent invention within a chuck is described next. First, the looselyfastened bracket assembly 30, FIG. 1, but for the disconnectedcantilever arm 18, is slid into position along the Y—Y axis of supportblock 8. Then the bracket is tightly clamped to the block 8 by bolts 16.As can be appreciated, the block 8 can be marked with graduations toaccurately measure the displacement that the cantilever arm 18 of thebracket extends above the top surface of the block 8. The chuck 10 isreceived in the support block as described above so as to be centrallypositioned, and keyway(s) 11 aligned with key(s) 6. The cutting depth isthe measured distance that the most forward cutting portion of the tapextends from the chuck (see “H” in FIG. 1). Upon inspection of FIG. 1,it can be seen that the cutting depth “H” is adjusted by sliding thebracket 30 up or down along axis Y—Y. Next, the cantilever arm 18 withthe first tap 20 already properly positioned therein, is guided so thetap 20 is received within the chuck at one end, and at its other end,the knurled thumb screw 19 or similar device is simultaneously guided tobe received in a threaded bore 21 having an opening in the top surfaceof an upwardly extending support arm 23 of the bracket. The central axisof the threaded bore 21 is parallel to the axis Y—Y of the support block8. Similarly, the longitudinal axis (not shown) of the upward supportbar 23 is also parallel to the axis Y—Y and the top surface of thesupport arm 23 is perpendicular to the Y—Y axis. The thumb screw 19 istightened to hold the cantilever arm 18 firmly against the top surfaceof the upward support arm 23. When the thumb screw 19 is tightened, thecantilever arm 18 is oriented perpendicular to the Y—Y axis. Upontightening of the thumb screw 19, the desired cutting depth “H” betweenthe most forward cutting portion of the tap 20 and the top of chuck isarrived at. The tap 20 is now properly oriented into its predeterminedand repeatable position with respect to the chuck. The chuck collet 40(see phantom lines and FIG. 4) is then rotated as well known in the artto lock against the tap 20 fixing the tap into its proper orientationwithin the chuck.

After the collet 40 is firmly tightened to hold the tap 20 in position,thumb screw 19, FIG. 1, is loosened and removed so that the cantileverarm 18 may then be removed from the cutting end of the tap 20. Thecantilever arm 18 is removed from the tap by either manually holding thechuck 10 or cantilever arm 18 in position and rotating the other(normally in a counterclockwise direction) so as to unthread the tap 20from the cantilever arm 18.

As well known in the art, the cooperating shanks of cutting tools, suchas the tap 20, are designed to have a geometry that cooperates withgripping surface on a chuck or collet. The surfaces on the chuck(collet) close on the tap 20 shank to lock the tap into position. Oncethe jaws are locked against the tap shank, the tap is securely held inposition and not subject to axial and angular displacement. As can beappreciated, the chucks/collets employed in industry firmly fasten metalcutting tools within the chuck/collet so as to resist the substantialforce and torques that arise during tapping and/or other metal cuttingoperations. Therefore, whenever a person manually rotates the chuckrelative to the cantilever arm, the threaded connection between the tap20 and cantilever arm 18 will disengage, not the coupling between thecollet 40 and tap 20.

FIGS. 6A–6H illustrate the progression of the formation of internalthreads in a workpiece 50, using two different tap series embodiments ofthe present invention, FIGS. 6A–6C and FIGS. 6E–6G. The workpiecematerial is a hard material, for instance workpiece 50 may be made froma heat treated hardened steel. This process would work equally well insoft materials or tough alloys. The internal threads are cut byemploying three taps 61, 62, 63, similar to the geometry of the tapshown in FIG. 2, these taps 61, 62, 63 are used sequentially to cut thethreads deeper and deeper into the workpiece in accordance with theinvention. FIGS. 6A–6C illustrate a tap series where the pitch diameterof each successive tap increases to form deeper threads. FIGS. 6E–6Hillustrate a tap series 67, 68, 69 where the pitch diameter is constantand the major thread diameter is a variable to produce the differentdepths of cut. Both tap series methods will produce acceptable threads.In FIG. 6A, near the bottom, 65 illustrates an internal sidewall of atap drill bore prior to the initiation of tapping. The frustoconicalphantom lines in FIG. 6A represent the desired internal threads in thefinished product.

Near the top of FIG. 6A, a partial view of the first pilot tap 61 isillustrated. The first pilot tap 61 cuts out a frustoconical threadedportion from the interior sidewall 65, represented by thecross-hatching. This embodiment illustrates a tap with increasing pitchdiameters. As can be seen in the partial drawings of the first pilot tap61 in FIG. 6A, the first tap has a pitch diameter “C”, that is slightlylarger than the diameter of the smooth pilot bore. Near the bottom ofFIG. 6B, the shallow internal threads 66 that were cut by the firstpilot tap are illustrated. In FIG. 6B, a second tap 62 having a largerpitch diameter “C” is next employed to cut the internal threads evendeeper into the workpiece 50, represented by the cross-hatching in FIG.6B.

In FIG. 6C, near the bottom, the internal thread cut out by the secondtap 62 is shown. Finally, a third tap 63 having even a greater pitchdiameter “C” than the second tap 62 is employed to cut out the remainingmaterial, represented by cross-hatching, to form the finished internallythreaded bore having the desired pitch and thread depth. FIG. 6Dillustrates the internal threads in the finished product.

FIGS. 6E–6G illustrate a second series of alternative taps that can bealigned for cutting/forming bore threads in accordance with theapparatus and method of the present invention. In this tap series themajor diameter “C” of the taps 67, 68, 69 are respectively increasedwhile the pitch diameter remains constant. The crosshatched areas inFIGS. 6E–6G represent material that is removed/cut from the tap drillbore 65. In FIG. 6F tap 68 with the same pitch diameter, but a largermajor diameter “C” than tap 67 is used to remove more material from thethread form 70 previously produced. The crosshatched area in FIG. 6Frepresents the material being removed by tap 68. To complete the threadform, tap 69, see FIG. 6G, will remove/cut the remaining workpiecematerial as shown in the crosshatched area. This will also result in afinal thread form illustrated in FIG. 6H.

FIGS. 6A–6D and 6E–6H illustrate the formation of the internal threadsimmediately adjacent the opening of a bore formed within a workpiece 50.It should be appreciated that the tapping process of the invention isnot intended to be limited to forming a threaded bore equivalent to onlytwo bolt revolutions, but the taps and tapping method of the inventioncan be used to tap very deep holes wherein the finished internal threadsmay even exceed the equivalent of three dozen revolutions. Inmanufacturing deeper holes with a greater number of thread revolutionsand/or in harder materials wherein greater torques are applied to thetaps, it is contemplated that more than three taps may be necessary tocut the internal threads. For each individual application, the torqueapplied during cutting actions, the material from which the tap isconstructed, the workpiece material, the dimensions of the tap(diameter) and other physical parameters will determine the number oftaps that are necessary to sequentially cut out internal threads intothe workpiece.

The bracket assembly 30, FIG. 1, in the present invention is made fromsteel, but alternatively could be made from metals or rigid materials,including but not limited to Aluminum, brass, plastic and glass.

No specific configuration of the cooperating locking jaws and shank ofthe tap are considered critical to the invention. It is contemplatedthat most any wellknown collet or other tool holding system can be usedin to hold a tap.

The invention tap is made of high speed steel (HSS), but it can beproduced from other materials in order to improve the function of thetaps. Taps are often used to produce threads in various semi-hard andtough materials. For instance, the hard material may be titanium or atitanium-based alloy.

In manufacturing the bracket 30, the downward surface 25, FIG. 3, on thecantilever arm 18 is ground smooth after the though bore 15 is drilledtherein so as to remove any burrs that may exist after drilling. A flathorizontal downward surface is required to cooperate with a top flathorizontal surface on the upwardly extending support arm 23 FIG. 1.

The embodiment disclosed and illustrated provides a method for fixingthe position of threading taps, but it is contemplated that this methodof aligning tools used in sequence could be used to properly orientother metalworking tools that are used in sequence to machine products.

Other applications, embodiments and variations to the disclosedembodiments described herein will be apparent to those skilled in theart and may be made without departing from the spirit and scope of theinvention as defined in the appended claims.

1. An alignment assembly for positioning a tap inside a chuck, theassembly comprising: a support block having a central longitudinal axis,and said support block adapted to receive said chuck; a fastenerfastened to said support block; an upwardly extending support arm havingopposite ends wherein the support arm is connected at one of saidopposite ends to the fastener; a cantilever arm, and the support arm isconnected at other of said opposite ends to the cantilever arm; saidcantilever arm containing a threaded bore adapted to receive the tap;and wherein the threaded bore presents a configuration having a bottomwith a geometry that substantially conforms to the geometry of thebottom of the tap.
 2. An alignment assembly for positioning a tap insidea chuck, the assembly comprising: a support block having a centrallongitudinal axis, and said support block adapted to receive said chuck;a fastener fastened to said support block; an upwardly extending supportarm having opposite ends wherein the support arm is connected at one ofsaid opposite ends to the fastener; a cantilever arm, and the supportarm is connected at other of said opposite ends to the cantilever arm;said cantilever arm containing a threaded bore adapted to receive thetap; and wherein the threaded bore presents a threads having a pitch andgeometry substantially similar to an internal thread desired to beformed by the tap.
 3. An alignment assembly for positioning a tap insidea chuck, the assembly comprising: a support block having a centrallongitudinal axis, and said support block adapted to receive said chuck;a cantilever arm operatively connected to said support block, and saidcantilever arm containing a threaded bore adapted to receive the tap;and wherein the threaded bore presents a configuration having a bottomwith a geometry that substantially conforms to the geometry of thebottom of the tap.
 4. An alignment assembly for positioning a tap insidea chuck, the assembly comprising: a support block having a centrallongitudinal axis, and said support block adapted to receive said chuck;a cantilever arm operatively connected to said support block, and saidcantilever arm containing a threaded bore adapted to receive the tan;and wherein the threaded bore presents a threads having a pitch andgeometry substantially similar to an internal thread desired to beformed by the tap.